Technical Field
The present invention is directed to systems that generate a current of electrical energy and additionally detection systems and methods that detect fluorescence, luminescence, chemiluminescence or phosphorescence signatures in the form of an electrical signal conducted by metallic structures.
Background of Related Art
The identification and quantification of proteins and other biomolecules using bioassays are of great importance in biomedical and biochemical applications.1-3 Fluorescence is the dominant technology in most of these applications, where a biomolecule of interest is detected by fluorescence emission from its fluorophore labeled binding partner.4,5 Fluorescence-based bioassays those carried out on planar surfaces generally lack sensitivity and require expensive optical instruments.6, 7 In addition, the biorecognition events in these assays are inherently slow (several minutes to hours).6, 7 The sensitivity of the fluorescence-based assays can be improved, without the use of high-end optical instruments, by incorporating plasmon resonant particles (PSPs) into these assays.8, 9 The improved sensitivity is made possible by the increase in fluorescence signatures and decreased lifetimes of fluorophores placed in close proximity to PSPs, described by a phenomenon called Metal-Enhanced Fluorescence (MEF).8, 10 In MEF-based bioassays, PSPs (generally silver nanoparticles) are deposited onto the planar surface and the bioassay is constructed on the PSPs.8 Since the size of most biomolecules are smaller than PSPs (20-100 nm), fluorophores are positioned within a distance where their emission is increased due to their interactions with the surface plasmons of PSPs.10 
The interactions of luminescent species with the close-proximity metallic nanoparticles have been extensively studied. These near-field interactions, are for the most part very complex, but can simply be understood phenomenologically as due to a close-proximity fluorophore inducing a mirror dipole in the metal, which in turn radiates the coupled quanta, in the form of emission, FIG. 1A. This interaction has been appropriately previously called “Metal-Enhanced Fluorescence”.
For decades fluorescence-based technologies have relied on photo detectors to convert photon fluxes into digital signatures such as photomultiplier tube or charge coupled device (CCD) camera. Nearly all such instruments encompass one or more of these types of detectors. However, such detectors are expensive and require an additional piece of equipment. Thus it would be advantageous to detect fluorescence, luminescence, chemiluminescence, bioluminescence or phosphorescence signatures in the form of an electrical signal conducted by metallic structures.